Within their lifetime, 1 in 8 women will be diagnosed with breast cancer, and the degree of psychological distress and impairment in physical functioning accompanying diagnoses and treatment have been prospectively related to quality of life (QOL) and morbidity. While prior work suggests that exercise may enhance mental and physical health, the efficacy of exercise to promote psychological and physical functioning has not been adequately assessed nor have factors related to exercise compliance been investigated. Over a 5-year period, we will implement an exercise intervention and evaluate its effects on psychological distress, fitness, body composition, and QOL among stage I and II breast cancer patients. We will also evaluate the pathways which may mediate exercise effects on QOL and assess exercise adherence factors. Women (N =140) drawn from West Virginia University's Mary Babb Randolph Cancer Center and the surrounding communities will be randomly assigned to either a 1-year exercise intervention or a control condition with assessments at baseline, 3, 6, and 12 months. Assessments will consist of a graded exercise test assessing cardiovascular fitness, body composition and strength analyses, and a psychosocial survey assessing psychological distress and QOL for which women will be compensated 40 dollar per assessment. Exercise group participants will be provided individualized walking and resistance training exercise programs inclusive of laboratory monitored and home-based phases. The intervention will also utilize cognitive-behavioral techniques such as contingency planning, goal setting, and self-monitoring to promote exercise adherence. The education-standard of care control group will be provided with general information regarding healthy lifestyle management, but will not receive a formal exercise prescription nor undergo the intervention experience in solidifying and acting on this information. Beyond comprehensively testing the efficacy of a low cost aerobic exercise intervention to promote physical and mental health, the project will also generate information which may be useful for promoting exercise among persons of low income.